Method for determining trace metal impurities in electronic-grade hydroxylamine

Abstract

The invention discloses a method for determining trace metal impurities in electronic-grade hydroxylamine, which comprises the following steps: diluting a hydroxylamine sample by preparing a composite extracting solution which has a pH value of 5.5 + / -0.2 and contains ammonium citrate, ammonium acetate and EDTA (Ethylene Diamine Tetraacetic Acid), effectively inhibiting hydroxylamine decomposition and stabilizing metal ions, and determining trace metal impurities in electronic-grade hydroxylamine by combining a triple quadrupole inductively coupled plasma mass spectrometry technology. The interference of polyatomic ions is eliminated by utilizing the cooling atomization and dynamic reaction tank functions, and finally, quantification is performed by adopting a matrix-matched standard curve method. The method solves the technical problems of low metal ion detection recovery rate and poor accuracy caused by chemical instability of electronic-grade hydroxylamine, has the advantages of safety in operation, high sensitivity, stable recovery rate and the like, and provides a reliable analysis means for quality control of key chemicals in a semiconductor manufacturing process.

Description

Technical Field

[0001] This invention relates to the field of semiconductor ultra-high purity electronic chemical analysis technology, specifically to a method for determining trace metal impurities in electronic-grade hydroxylamine. Background Technology

[0002] Electronic-grade hydroxylamine (NH2OH) is a key cleaning agent in the chemical mechanical polishing (CMP) process for semiconductor copper interconnects. Trace metal impurities (such as Fe, Cu, Ni, Zn, etc.) in it directly affect the gate oxide integrity and final yield of the chip. Therefore, the metal ions in electronic-grade hydroxylamine must be strictly controlled at the ppb or even ppt level.

[0003] Currently, inductively coupled plasma mass spectrometry (ICP-MS) is widely used in the industry for the detection of trace metal impurities in electronic-grade hydroxylamine due to its extremely low detection limits (down to ng / L or ppt levels), wide linear dynamic range, ability to analyze multiple elements simultaneously, and high analytical efficiency. For example, patent specifications with publication numbers CN120987276A and CN120987277A both disclose the use of inductively coupled plasma mass spectrometry (ICP-MS) to detect the metal ion content in aqueous hydroxylamine samples.

[0004] However, the inherent strong reducing properties and chemical instability of hydroxylamine pose significant challenges to its trace metal analysis. For example, traditional high-temperature / strong acid digestion processes can easily trigger violent decomposition of hydroxylamine, posing significant safety hazards. After dilution with ultrapure water, metal ions are prone to valence state changes during sample detection, leading to adsorption on the container walls or the formation of hydroxylamine-metal complexes, resulting in metal ion loss and morphological distortion. Furthermore, the high-concentration hydroxylamine matrix itself can form ArN with argon (Ar) during the ionization process of ICP-MS measurement. + ArO + ArNH + ArNO + Polyatomic ions severely interfere with the accurate measurement of key metallic elements such as Mn, Fe, Cu, Zn, As, and V.

[0005] Therefore, it is crucial to develop a method that can safely, accurately, and with high sensitivity determine trace metals in electronic-grade hydroxylamine. Summary of the Invention

[0006] To address the aforementioned technical problems and shortcomings in this field, this invention provides a method for determining trace metal impurities in electronic-grade hydroxylamine. This invention constructs a comprehensive solution integrating in-situ stabilization, matrix matching, and multi-mode interference elimination, achieving safe, accurate, and highly sensitive detection of 18 metal elements. Under ISO Class 100 cleanroom conditions, the method achieves a metal element recovery rate consistently between 90% and 110%, with a method detection limit ≤0.1 μg / kg, providing reliable analytical technology support for closed-loop quality control in advanced semiconductor processes.

[0007] The specific technical solution is as follows: A method for determining trace metal impurities in electronic-grade hydroxylamine, comprising the steps of: (1) Ammonium citrate, ammonium acetate, and ethylenediaminetetraacetic acid (EDTA) were dissolved in ultrapure water to obtain a solution containing 0.05±0.01 M ammonium citrate, 0.05±0.01 M ammonium acetate, and 0.01±0.001 M EDTA. The pH of the solution was then adjusted to 5.5±0.2, preferably 5.5±0.1, with ammonia and / or acetic acid to obtain a composite extract. This composite extract can effectively inhibit the decomposition of hydroxylamine and stabilize trace metal ions through chelation, preventing their adsorption or precipitation.

[0008] (2) Sample dilution: The electronic grade hydroxylamine sample to be tested is diluted with the composite extract solution by a dilution factor of 50 to 100 times to ensure the stability of the metal ion form and obtain the sample test solution.

[0009] (3) Sample detection: The sample test solution was analyzed using a triple quadrupole inductively coupled plasma mass spectrometer (ICP-MS / MS, such as PE-5000G) equipped with a PC3Peltier cooling nebulizer system and a dynamic reaction cell DRC-MS / MS. The above-mentioned triple quadrupole inductively coupled plasma mass spectrometer achieves low matrix effect and high sensitivity detection of metallic impurities in the sample through the synergistic effect of the three stages of cooling nebulizer PC3Peltier-DRC-MS / MS.

[0010] (4) Quantitative analysis: Using the matrix matching principle, a series of metal concentration gradient standard calibration solutions (standard solutions) are prepared from the hydroxylamine solution in which no metal ions were detected, according to step (2). The standard calibration solutions are then tested according to step (3) to establish a calibration curve. The target metal element of the electronic-grade hydroxylamine sample is quantified based on the calibration curve. This invention uses the hydroxylamine solution in which no metals were detected as a matrix to prepare gradient standard solutions and create a standard curve, thereby maximizing the offsetting of matrix effects and ensuring quantitative accuracy.

[0011] This invention targets hydroxylamine, a strong reducing agent, which cannot be diluted with strong oxidizing agents such as nitric acid. However, if only ultrapure water is used as a diluent, the accuracy of metal impurity detection still needs improvement because hydroxylamine itself is easily decomposed and the trace metal ions within it are not stable enough. Based on this, this invention constructs a specific weakly acidic buffer system (pH=5.5±0.2, preferably pH=5.5±0.1) and introduces a specific combination of chelating agents (ammonium citrate, ammonium acetate, and EDTA) to effectively inhibit the decomposition of hydroxylamine itself, while stabilizing trace metal ions, ensuring that their form and concentration remain unaffected during the analysis process. This is something that traditional dilution methods cannot achieve.

[0012] In some preferred embodiments, the method for determining trace metal impurities in electronic-grade hydroxylamine uses a soluble polytetrafluoroethylene (PFA) container pretreated as follows: the sample test solution and standard calibration solution are distilled and washed at 150°C–180°C with a nitric acid solution of 5% or higher (e.g., 10%) for 12–24 hours, followed by rinsing with ultrapure water until the background metal concentration of the PFA container is confirmed by ICP-MS to be below 0.02 ng·L⁻¹. -1 .

[0013] In the method for determining trace metal impurities in electronic-grade hydroxylamine according to the present invention, the resistivity of the ultrapure water at 25°C is preferably not less than 18.2 MΩ·cm.

[0014] In some preferred embodiments, in step (3), the operating temperature of the Peltier cooling atomizing system PC3Peltier is set to -5℃±1℃.

[0015] In some preferred embodiments, in step (3), the reactant gases in the dynamic reaction cell include oxygen and ammonia. This invention employs a triple quadrupole inductively coupled plasma mass spectrometer equipped with a Peltier cooling atomization system (PC3Peltier) and a dynamic reaction cell (DRC-MS / MS). This configuration effectively reduces solvent load and matrix effects through deep cooling, and efficiently eliminates NH2 through the flexible application of reactant gases (oxygen and ammonia) in the DRC. + OH - N2 + ArN + ArO + ArNH + ArNO + ArC + and ArCH + Interference of multi-atomic ions on the target element.

[0016] More preferably, in step (3), the oxygen flow rate is 0.4~0.6 mL / min. -1The flow rate of the ammonia gas is 0.3~0.6 mL / min. -1 .

[0017] In some preferred embodiments, in step (4), the calibration curve is constructed using the weighted least squares method, with weight = 1 / concentration, and a quadratic polynomial correction is used during curve extrapolation to compensate for nonlinearity in the high concentration region.

[0018] In step (4), the target metal element includes one or more of the following: sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), molybdenum (Mo), silver (Ag), tin (Sn), and barium (Ba).

[0019] In some preferred embodiments, the entire detection process for determining trace metal impurities in electronic-grade hydroxylamine is performed in an ISO Class 5 or higher cleanroom environment.

[0020] This invention utilizes a composite extraction solution (containing ammonium citrate, ammonium acetate, and EDTA) with a specific pH value (5.5±0.2) to dilute hydroxylamine samples, effectively inhibiting hydroxylamine decomposition and stabilizing metal ions. Combined with triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS / MS), its cooling atomization and dynamic reaction cell functions eliminate polyatomic ion interference. Finally, quantification is performed using a matrix-matched standard curve method. This invention solves the technical problem of low recovery rate and poor accuracy in metal ion detection caused by the chemical instability of electronic-grade hydroxylamine. It offers advantages such as safe operation, high sensitivity (detection limit ≤0.1µg / kg), and stable recovery rate (90%~110%), providing a reliable analytical method for quality control of key chemicals in semiconductor manufacturing processes.

[0021] Compared with the prior art, the beneficial effects of this invention are as follows: 1) High-efficiency extraction of metal ions: In-situ stabilization is achieved through a mild compound extraction solution, which effectively inhibits the decomposition of hydroxylamine. Trace metal ions are stabilized through chelation to prevent adsorption or precipitation, thus completely avoiding the safety risks associated with high-temperature digestion. The pretreatment process is also simple and safe.

[0022] 2) High sensitivity and accuracy: The three-stage synergistic interference elimination technology of cooled atomized PC3Peltier-DRC-MS / MS pushes the detection limit of multiple metal elements to 0.1μg / kg, and the metal element recovery rate is stable at 90%~110%, which meets the control requirements of semiconductor manufacturing processes for metal impurities and provides a safe, sensitive and repeatable analytical method for the quality control of key chemicals.

[0023] 3) Good stability: The compound extract can effectively prevent the decomposition of hydroxylamine and the loss of metal ions, ensuring the stability of the analytical results over time.

[0024] 4) High practicality: This invention provides a reliable and accurate analytical technique for monitoring the extreme purity of electronic-grade hydroxylamine in the semiconductor industry. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise specified, the resistivity of the ultrapure water used below at 25°C is not less than 18.2 MΩ·cm.

[0026] This invention provides a method for determining trace metal impurities in electronic-grade hydroxylamine. Its core innovation lies in constructing a ternary synergistic technology system—in-situ stabilization, matrix matching, and multi-mode interference elimination—to solve the quantitative challenges posed by the chemical instability of hydroxylamine, thus achieving accurate and safe analysis of trace metal impurities in electronic-grade hydroxylamine. The specific implementation is as follows: I. Preparation of the compound extract: Take a clean 1 L PFA bottle and add approximately 800 mL of ultrapure water with a resistivity ≥18.2 MΩ·cm. Add 12.2 g ammonium citrate (final concentration 0.05 M) and 3.85 g ammonium acetate (final concentration 0.05 M) sequentially, stirring magnetically until completely dissolved. In a separate beaker, dissolve 2.92 g EDTA (final concentration 0.01 M) in a small amount of ultrapure water and ammonia, and quantitatively transfer the dissolved EDTA to the aforementioned PFA bottle. While continuously stirring, adjust the pH of the solution to 5.5 ± 0.1 with high-purity ammonia and / or high-purity acetic acid. Make up to 1.0 L with ultrapure water, mixing thoroughly to obtain the composite extract, which is ready for use.

[0027] II. Sample Preparation: Take a pretreated 15 mL PFA centrifuge tube and accurately add 9.80 mL of the composite extraction solution. Using a calibrated pipette, accurately pipette 200 μL of electronic-grade hydroxylamine sample (50 wt% aqueous solution) and slowly add it to the centrifuge tube. Tighten the cap and vortex for 3 minutes to thoroughly mix.

[0028] Simultaneous blank preparation: Take a pretreated 15 mL PFA centrifuge tube, accurately add 9.80 mL of composite extract, and add 200 μL of ultrapure water. Vortex for 3 minutes.

[0029] Filtration: All prepared solutions (including subsequent standard solutions) must be passed through a 0.45 μm pore size needle filter (PP material, pre-soaked in >5 vol% high-purity nitric acid for 24 h and rinsed until neutral) before being used to prevent clogging of the ICP-MS injection system.

[0030] Note: All sample preparation operations were performed in an ISO Class 100 cleanroom fume hood. All PFA containers used were immersed in 10 vol% high-purity nitric acid for 24 hours, followed by repeated rinsing with ultrapure water until neutral, and passed testing (ICP-MS analysis confirmed that the background metal concentration of the PFA containers was below 0.02 ng·L⁻¹). -1 Use after that.

[0031] III. Preparation of a series of standard addition samples: Five sample test solutions (STD1~STD5) were prepared consecutively from hydroxylamine samples in which no metal ions were detected, following section "II. Sample Preparation". These solutions served as the base solutions for the standard addition method. In a cleanroom fume hood, PE multi-element calibration standards (N9303837 100μg / mL: As, Be, Ca, Cd, Co, Cr, Cu, Fe, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Tl, V, Zn, 100 mL 21-element multi-element mixed standard solution) were added to the base solutions after stepwise dilution by gravimetric method (or high-precision pipette). Prepare mixed metal standard solutions (STD-1 to STD-5) containing metal elements at concentrations of 0.01, 0.05, 0.1, 0.5, and 1.0 ng / g (i.e., 0.01, 0.05, 0.1, 0.5, and 1.0 ng / g spiked to the substrate). After all standard solutions have been prepared, vortex them again to mix thoroughly.

[0032] IV. Optimization of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Detection Conditions: Instrument model: PE 5000G (High-resolution inductively coupled plasma mass spectrometry).

[0033] A 200 ng / L tuning solution was prepared from a hydroxylamine sample in which no metal ions were detected, according to the gravimetric method described in Section II, Sample Preparation. 6 Li, 9 Be、 24 Mg 56 Fe、 115 In、 208 Pb, 238U). Using this matrix-matched tuning fluid, key parameters such as sample lift rate, atomization chamber temperature, RF power, plasma gas flow rate, and auxiliary gas flow rate were systematically optimized. Cooling the atomizer to -5℃ can reduce Ar... - The polyatomic ion strength was reduced to below 0.05%, which significantly suppressed the matrix effect of the hydroxylamine matrix. The optimal ionization conditions are shown in Table 1.

[0034] Table 1 Optimization Table of Key Ionization Parameters ArN generated during the ionization of the hydroxylamine matrix + ArO + ArC + To prevent interference from polyatomic ions, DRCO2 / NH3 will continue to be used as the reactant gas. 55 Mn, 56 The interference elimination rate of key elements such as Fe is as high as 99.9% or more, achieving Ar - Effective suppression of interfering ions by two orders of magnitude. Optimized reaction cell parameters are shown in Table 2.

[0035] Table 2 Optimized parameters for the reaction tank Note: In MSMS mode, Q1 screens target precursor ions, and Q3 detects characteristic product ions, achieving dual-mass MSMS screening; in MS Shift mode, Q1 screens target precursor ions (Ti). - (m / z = 48), Q3 detection of characteristic product ions (Ti(NH4)) x (m / z = 131), to achieve dual quality screening.

[0036] V. Preparation of Standard Curve and Sample Determination: 1. Standard curve creation: The standard solutions with mixed metal concentration gradients of 0.01, 0.05, 0.1, 0.5, and 1.0 ng / g prepared in "III. Preparation of Standard Addition Series Samples" were measured according to the detection conditions after "IV. Optimization of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Detection Conditions".

[0037] A standard curve was prepared using the standard addition method. A linear regression equation was established with the signal intensity (cps) of each metal element as the ordinate and the corresponding metal concentration (ng / g) as the abscissa.

[0038] 2. Sample determination: The sample to be tested, prepared according to "II. Sample Preparation", will be analyzed under the ICP-MS detection conditions in step four to determine the content of each metal element in the test solution. The actual content of metal elements in the sample (ng / g) will be calculated according to the following formula: C 样品 =(C 测定 -C 空白 )×A in: C 样品 This represents the actual concentration (ng / g) of the metal element in the electronic-grade hydroxylamine sample. C 测定 The concentration (ng / g) of the metal element in the test solution as determined by ICP-MS. C 空白 The concentration (ng / g) of metal elements in the synchronous blank solution as measured by ICP-MS. A: Dilution factor (in this example, it is 50 times, that is, 10 mL of diluent contains 0.2 mL of hydroxylamine sample, the dilution factor is 10 / 0.2 = 50).

[0039] Note: C 空白 The determination was performed using a standard curve based on the composite extract without the addition of hydroxylamine.

[0040] Example 1: Determination of the method detection limit (MDL): For samples where no metal ion hydroxylamine was detected, follow steps "II. Sample Preparation" and "III. Standard Addition Series Preparation" in the specific implementation plan, and based on the instrument conditions determined in "IV. Optimization of Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS / MS) Detection Conditions," proceed to "V. Preparation of Standard Curve and Sample Measurement." The sample is tested in parallel N times (N≥6, preferably N = 10), and the limit of detection (MDL) is calculated using the following formula: The calculation formula is: MDL = t × SD × A in: t: The t-value for the 99% confidence interval is 3.14 (N=10); SD: Standard deviation of N sample measurements; A: Dilution factor (in this example, it is 50 times, that is, 10 mL of diluent contains 0.2 mL of hydroxylamine sample, the dilution factor is 10 / 0.2 = 50).

[0041] Table 3 shows the detection lines for the linear equations and methods.

[0042] Table 3 Example 2: Method precision testing: Following the procedure outlined in "II. Sample Preparation," electronic-grade hydroxylamine samples were processed. Under the instrument conditions determined in "IV. Optimization of Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS / MS) Detection Conditions," hydroxylamine samples with known metal ions were continuously measured in parallel six times. The concentration (ng / g) of each target metal element was recorded for each measurement, and its average value (ng / g), standard deviation (SD), and relative standard deviation (RSD%) were calculated. The determination of the precision of the detection method is shown in Table 4.

[0043] Table 4 As can be seen from Table 4, the RSD% of each target metal element is less than 10%, indicating that the method of the present invention has good precision and can provide stable and reliable determination results.

[0044] Method accuracy test: Take an electronic-grade hydroxylamine sample of known concentration, process it according to the "II. Sample Preparation" procedure in the specific implementation method, and accurately add 1 ng / g of the target metal element standard solution. Under the instrument conditions determined in "IV. Optimization of Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS / MS) Detection Conditions", perform three consecutive parallel determinations of the spiked sample and take the average value. Calculate the recovery rate of each metal element according to the following formula: Formula for calculating recovery rate: Recovery rate (%) = (Measurement value of spiked sample - Measurement value of unspecified sample) / Spike amount × 100% The test results for the recovery rate are shown in Table 5 below.

[0045] Table 5 Results of metal element spiked recovery determination As can be seen from Table 5, the recovery rates of each target metal element are all in the range of 90% to 110%, indicating that the method of the present invention has good accuracy and can truly reflect the content of trace metal ions in the sample.

[0046] Comparative example: Metal element detection using ultrapure water dilution: Sample A of known concentration of electronic grade hydroxylamine was prepared in parallel. Sample B was diluted with ultrapure water and diluted with the composite extract specified in this invention. Based on the steps and instrument parameters described in "IV. Optimization of Inductively Coupled Plasma Mass Spectrometry Detection Conditions" and "V. Preparation of Standard Curve and Sample Determination", the spiked recovery rate and precision (expressed as relative standard deviation RSD%) of hydroxylamine metal element were compared under the two dilution conditions. The comparison data are detailed in Table 6 below.

[0047] Table 6 In hydroxylamine matrix systems using ultrapure water as the dilution medium, hydroxylamine is prone to chemical decomposition, leading to significant losses of metal ions through adsorption or precipitation. The recovery rates of most metal ions are significantly low, and signal fluctuations caused by matrix instability during testing result in relative standard deviations (RSD) exceeding 7% for parallel measurements.

[0048] This invention utilizes a mild, composite extract for in-situ stabilization, effectively inhibiting the decomposition of hydroxylamine, and stabilizes trace metal ions through chelation, preventing their adsorption or precipitation. The metal ion recovery rate is 90%–110%, with an RSD <5%, meeting the semiconductor industry's testing requirements for trace metal impurities in hydroxylamine.

[0049] In summary, this invention solves the quantitative problem caused by the chemical instability of hydroxylamine by constructing a ternary synergistic technology system of in-situ stabilization, matrix matching, and multi-mode interference elimination, and realizes accurate and safe analysis of trace metal impurities in electronic-grade hydroxylamine.

[0050] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for determining trace metal impurities in electronic-grade hydroxylamine, characterized in that, Including the following steps: (1) Dissolve ammonium citrate, ammonium acetate and EDTA in ultrapure water to obtain a solution containing 0.05±0.01 M ammonium citrate, 0.05±0.01 M ammonium acetate and 0.01±0.001 M EDTA, and then adjust the pH of the solution to 5.5±0.2, preferably 5.5±0.1, with ammonia and / or acetic acid to obtain a composite extract; (2) Sample dilution: The electronic grade hydroxylamine sample to be tested is diluted with the composite extract solution by a dilution factor of 50 to 100 times to ensure the stability of the metal ion form and obtain the sample test solution; (3) Sample detection: The sample test solution was analyzed by a triple quadrupole inductively coupled plasma mass spectrometer equipped with a PC3Peltier cooling atomization system and a dynamic reaction cell DRC-MS / MS. (4) Quantitative analysis: Using the matrix matching principle, a series of metal concentration gradient standard calibration solutions were prepared from the hydroxylamine solution in which no metal ions were detected in step (2). The standard calibration solutions were tested in step (3) and a calibration curve was established. The target metal element of the electronic grade hydroxylamine sample was quantified based on the calibration curve.

2. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1, characterized in that, The sample test solution and standard calibration solution were placed in PFA containers that underwent the following pretreatment: The containers were distilled and washed at 150℃~180℃ with a nitric acid solution of 5% or higher (v / v) for 12~24 h, followed by rinsing with ultrapure water until ICP-MS analysis confirmed that the background metal concentration of the PFA container was below 0.02 ng·L⁻¹. -1 .

3. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1 or 2, characterized in that, The resistivity of the ultrapure water at 25℃ is not less than 18.2 MΩ·cm.

4. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1, characterized in that, In step (3), the operating temperature of the Peltier cooling atomization system PC3Peltier is set to -5℃±1℃.

5. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1, characterized in that, In step (3), the reaction gas in the dynamic reaction tank contains oxygen and ammonia.

6. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 5, characterized in that, In step (3), the oxygen flow rate is 0.4~0.6 mL / min. -1 The flow rate of the ammonia gas is 0.3~0.6 mL / min. -1 .

7. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1, characterized in that, In step (4), the calibration curve is constructed using the weighted least squares method, with weight = 1 / concentration, and a quadratic polynomial correction is used during curve extrapolation to compensate for the nonlinearity in the high concentration region.

8. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1, characterized in that, In step (4), the target metal element includes one or more of sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, selenium, molybdenum, silver, tin, and barium.

9. The method for determining trace metal impurities in electronic-grade hydroxylamine according to claim 1, characterized in that, The method for determining trace metal impurities in electronic-grade hydroxylamine is performed entirely in an ISO Class 5 or higher cleanroom environment.

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